I have a 2013 prius v 5. I bought it new from the dealer, and it has now 40,000 miles. Lately, I've been having intermittent power failure problems. They happen when I try to turn off the power. The panel lights star acting up, and a buzzing noise is heard by the driver's side of the engine compartment. Then, it seems that the power drains, until there is no power at all. Everything I'm not able to power the car I jump it and it works. I doubt that it is the 12v battery, because when I jump it then it works for the whole day. But then the problem arises randomly. When the power drains there is a buzzing noise. Could it be a rely or some other electronic device failure? I have to keep a battery jumper with me, so that I can power the car when it fails. If anyone had a similar problem and was able to troubleshoot and fix it, please let me know. I've tried to talk to a service advisor at the Toyota dealer where I bought it but they are always too busy and don't return my calls, so far. I need the car to work, and it's a hassle to do with out it while they fix it. But I certainly can afford to have the car several times at the shop if they fail to find the issue.
Still sounds like the 12v battery is weak/bad. Get a volt meter or multimeter and measure the battery voltage when the car is off. The buzzing sound by the driver's side is the brake booster accumulating pressure, it's normal.
Are you saying the buzzing continues for more than a few minutes? Sometimes the brake booster is more obvious in a garage than when you shutdown outside. Lights on (map lights and trunk lights especially) will drain a battery overnight. A replacement 12v battery will be around $300 at the dealer or perhaps $175 online, but if you need it you need it. Here's a link on how to check the 12v voltage that might work if the car will go into accessory mode. Prius v Display Audio Service Menu w Battery Check | PriusChat
welcome! possibly, you 12v battery is still under warranty. if you don't want to buy a 10 dollar meter and check the 12 volt battery yourself, make an appointment with toyota, or any auto parts store can test it and replace it if necessary. 'assuming', is a bad look for the prius. all the best!
As I read your post I kept thinking that it should be a warranty item. Then reading your last paragraph, I'd say: email the dealership's service manager, outlining the problem and your difficulty getting attention. If nothing comes of that, contact corporate Toyota. Maybe drop a hint with the service manager that that's your next course, say ask if he can suggest a contact email.
I have the same issue. It acts like a loose battery cable but both are tight. I had his issue with an aftermarket battery so I replaced it with a new dealer battery and the problem is back 10 Months later. I have to ask the dealer parts department.
